The CZ guide rod has been plastic for many years. And for the alloy-framed guns (PCR, P01, etc.) it's really important that you KEEP the guide rod plastic. (Delrin, actually.) The shorter barrel makes the guide rod travel in a greater vertical arc as the slide cycles, and with a metal guide rod and alloy frame, you eventually will get some receiver stop wear (that's where the guide rod rests). By bending, the plastic guide rod (which is a full-length guide-rod in the compact models) is simply flexing rather than staying straight. It's not guiding the recoil spring at that point, as the spring is compressed when it's free to bend. (I think the guide rod is mostly used to install that darned spring, as once it's in the gun, the slide encloses it and keeps it in a relatively small channel.)
I've never heard of a functional problem with the plastic guide rods, except one CZ-97 that came from the factory with a screwed up plastic guide rod -- they couldn't rack the slide straight out of the box.
I've shot tens of thousands of rounds through compact, full-size CZs, 97s, etc., and never had a problem. At the range and in competition. I've had pre-Bs with metal guide rods, and never could tell a functional difference; the same for the CZ that could use full-length guide rods -- full-length or truncated didn't seem to make a difference.
SIG has a similar problem with folks getting upset about plastic guide rods in their guns about 10 years ago. They finally changed back, as a public relations sop to customers, but not because the steel guide rod made the gun work better. Glock, on the other hand, has used plastic guide rods for years, and they seem to work even if they break.
You can consider the use of the plastic guide rod as a cheapening of the design, but its really a more functional change. And since the part is a non-stressed piece, whether it's plastic or metal is essentially irrelevant (unless you have an alloy-framed gun.) With an alloy framed gun, a metal guide rod would actually damage the gun, over time.
Roll pin rust? I've NEVER heard of a single CZ roll pin rusting through, and I've been following these guns for a lot of years. (Never really heard about it in other guns, for that matter.) Perhaps if you carried and stored the gun in a highly salty or otherwise corrosive or moist environment it could be a problem. But you can get the replacement parts from CZ for almost nothing, and have spares if you really think it's a potential problem.
As for solid pins: I wouldn't be surprised if those solid steel pins worked their way out over time, unless you've staked them. But staking them makes them difficult to get out. That was a problem with the earlier (pre-B) models. (I had a number of those models, too.)
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